Not that it is at all likely, but is it too late for Cochran to file as an independent?
(Not that he has any chance in hell of winning).
I believe so, the filing deadline was like March 31st. That being said MS has easy ballot access laws, one merely has to form a "party" with an official address and elected party "officers" in order to get on the ballot, Thus if it's not to late a "Connecticut for Lieberman" knockoff party type effort is entirely possible.
If McDaniel ends up winning the run-off, I'd call this the best possible outcome.
At the best, a three-way race with a lot of crossover Democrats throws the election to Cochran. At its worst, Thad doesn't even campaign but is able to garner enough vote to elect Childers as Senator.